The SiO2 and amorphous SiO2-Al2O3 (ASA) was prepared by stepwise precipitation method,and the Ni2P/ASA catalyst was fabricated by saturated volume impregnation and programmed-temperature reduction.Characterizations of the supports and catalysts were performed using XRD,FT-IR,N2 adsorption-desorption,H2-TPR and TEM,and then the effects of SiO2/Al2O3 mass ratio and specific surface area obtained with ASA on the Ni2P formation were mainly investigated.Results showed that with the increasing of Al2O3 content in ASA support the more content of P was required for the formation of Ni2 P phase.Phosphorus firstly formed AlPO4 phase with alumina,hindered the formation of phosphorus-rich atmosphere,however phosphorus-rich atmosphere was pre-requisited to the formation of Ni2P phase,hence more P must be added to the carrier with more aluminum content to produce pure Ni2P phase.TEM results indicated that the formation of AlPO4 phase,in turn,promoted the reduction of Ni2P particle size and facilitated the dispersion of the catalyst.The specific surface area of the support has little influence on the formation of Ni2P phase.%用分步沉淀法制备了SiO2和不同SiO2/Al2O3质量比的无定形SiO2-Al2O3(ASA),采用饱和体积共浸渍和程序升温还原法制备Ni2P/ASA催化剂,以X射线衍射、红外光谱、N2吸附脱附、H2还原脱附和透射电镜对载体和催化剂进行表征,重点考察了低温条件下不同SiO2/Al2O3比以及不同比表面积大小对Ni2P相生成的影响.结果表明,在低温条件下,随载体中氧化铝含量增多,生成Ni2P相所需的P含量增多.原因是磷首先与氧化铝生成AlPO4相,阻碍了富磷气氛的生成,而生成Ni2P相必须在富P的气氛下进行,从而在铝含量较多的载体中必须加入更多的P含量才能生成纯Ni2P相.TEM结果表明,AlPO4相的生成反过来促进了Ni2P颗粒尺寸的降低,有利于催化剂的分散.载体比表面积大小对Ni2P相的生成影响不大.
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